EXHIBIT 5(a)


                            THELEN REID & PRIEST LLP
                               40 West 57th Street
                          New York, New York 10019-4097

                                  May 10, 2000

Texas Utilities Company
(doing business as TXU Corp.)
1601 Bryan Street
Dallas, Texas 75201

Ladies and Gentlemen:

               Referring to the Registration Statement on Form S-8 filed by
Texas Utilities Company, doing business as TXU Corp. ("Company"), on
December 21, 1999 (File No. 333-93181) as amended by the Post-Effective
Amendment No. 1 filed on December 22, 1999 and the Post-Effective Amendment
No. 2 to be filed on or about the date hereof (together, the "Registration
Statement") with the Securities and Exchange Commission ("Commission") under the
Securities Act of 1933, as amended, for the registration of (i) up to 4,000,000
shares of the Company's common stock, without par value ("Stock") and the
attached Preference Stock Purchase Rights (the "Rights"), to be offered from
time to time in connection with the Employees' Thrift Plan of the Texas
Utilities Company System and the ENSERCH Corporation Employee Stock Purchase and
Savings Plan (together, the "Plan") and (ii) an indeterminate amount of
interests in the Plan, we are of the opinion that:

               1.   The Company is a corporation validly organized and existing
under the laws of the State of Texas.

               2.   All requisite action necessary to make any shares of
authorized but unissued Stock validly issued, fully paid and non-assessable and
to make valid the interests in the Plan will have been taken when any shares of
authorized but unissued Stock shall have been issued and delivered for the
consideration contemplated in the Plan.

               3.   The Rights, when issued as contemplated by the Registration
Statement will be validly issued.

               We are members of the New York Bar and do not hold ourselves out
as experts on the laws of the State of Texas. As to all matters of Texas law, we
have with your consent relied upon an opinion of even date herewith addressed to
you by Worsham Forsythe Wooldridge LLP, of Dallas, Texas, General Counsel for
the Company, which is being filed as an exhibit to the Registration Statement.

               We hereby consent to the use of our name in the Plan prospectus
in relation to our review of the statements of law and legal conclusions under
the caption "Federal Income Taxes" and to the filing of this opinion with the
Commission as an exhibit to the Registration Statement.

                                        Very truly yours,

                                        /s/ Thelen Reid & Priest LLP

                                        THELEN REID & PRIEST LLP